Dr. Tydell is a post-doctoral fellow in the Department of Pathology at the University of California, Irvine College of Medicine. She obtained her DVM degree at the University of California, Davis and practiced clinically in small animal emergency and critical care. Dr. Tydell has returned to academia to develop a career in immunology research. The focus of this proposal is a novel microbicidal protein of the innate immune system. The critical role of innate immunity in human health has gained substantial recognition over the last decade. The innate immune system destroys or contains infection prior to the response of adaptive immunity. It also modulates the responses of the adaptive immune system. A novel family of proteins, peptidogly can recognition proteins (PGRP), has been characterized and demonstrates activity that may be compatible with a pattern-recognition function in the innate immune system. An RP-HPLC method of purifying a mammalian PGRP, termed bovine oligosaccharide binding protein (bOBP), has been developed, bOBP's disulfide motif, sequence and cDNA have been characterized. It shares 74% sequence similarity with a human PGRP. bOBP is the first PGRP demonstrated to be microbicidal. It kills gram-positive bacteria, gram-negative bacteria and yeast in Iow micromolar concentrations. Found in neutrophil and eosinophil granules, bOBP is secreted upon stimulation of the cells with butyrate or phorbol myristate acetate. In establishing herself as an independent researcher, Dr. Tydell will 1) define the scope of bOBP's antimicrobial activity through antimicrobial screens followed by microbicidal assays; 2) determine the molecular constituents of microbial cell envelopes that bind bOBP in assays with tritiated LPS; 3) identify the intracellular organelles that contain bOBP with immunogold electron microscopy and; 4) elucidate cellular secretion of bOBP in Western blot analysis of secretion assays. The goal of this work is an understanding of the PGRP family of proteins' role in human health.